Molded resin casing of electronic part with flexible flat cable

ABSTRACT

A molded resin casing of an electronic part equipped with a flexible flat cable and internally accommodating a board on which are formed electric conductor patterns slidingly contacted by contacts of a slider of the electronic part, includes a flexible board having various electric conductor patterns formed on a synthetic resin film used as the board. The flexible board is formed integrally with a flexible flat cable comprising a synthetic resin film on which are formed electric conductor patterns electrically connected to the aforementioned various electric conductor patterns. When the molded resin casing is molded by injecting a molten synthetic resin, the flexible board is inserted in such a manner that the electric conductor patterns are exposed within the casing, thereby integrating the flexible board and synthetic resin casing, with the flexible flat cable extending outwardly from a side portion of the synthetic resin casing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

An electronic part such as a rotary- or sliding-type variable resistor,a rotary- or sliding-type code switch or the like which finds use inelectronic apparatus includes a board on which various patterns areformed by printing, a casing, and a slider having contacts brought intosliding contact with the patterns formed on the board. The board isfixed to the bottom of the casing and the slider is supported on theboard so as to rotate or slide freely. The components such as the board,the casing and the slider are manufactured as separate elements and aresubsequently assembled into a finished electronic part by an assemblyprocess.

2. Description of the Related Art

As the result of success in achieving a reduction in the size andthickness of electronic parts, it has also been attempted to reduce thesize and thickness of the casings for rotary- or sliding-type variableresistors and rotary- or sliding-type switches in recent years. However,since the rotary- and sliding-type electronic parts of the conventionalconstruction are composed of elements that are manufactured separatelyand then assembled into a while, there is a limitation upon the size andthickness reduction that can be achieved. The more progress that is madein reducing size and thickness, the more difficult it is to assemble theindividual elements into the finished product.

Furthermore, when an electronic part of reduced size and thickness isinstalled in an electronic apparatus and lines such as signal lines areconnected between the part and the external apparatus, it is difficultto connect the lines to the miniature terminal portion of the electronicpart and the connections involve problems in terms of reliability.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to solve theaforementioned problems and provide a molded resin casing of anelectronic part equipped with a flexible flat cable in which a flexibleboard and a flat cable are integrally formed of a thermoplasticsynthetic resin film. The flexible flat cable is composed of a basethermoplastic resin film on which conductive patterns are disposed. Theflexible board is inserted in a molded synthetic resin casing, therebyintegrating the board, the casing and the flexible flat cable todispense with the need to assemble the board and the casing, thus makingpossible a great reduction in size and thickness required for modernelectronic parts and dispensing with the need to connect a cable to theterminal portion of the electronic part.

According to the present invention, the foregoing object is attained byproviding a molded resin casing of a rotary- and sliding-type electronicpart internally accommodating a board on which are formed electricconductor patterns slidingly contacted by contacts of a slider of theelectronic part, wherein a board portion and a flexible flat cableportion are integrally formed on a film comprising a thermoplasticsynthetic resin material, electric conductor patterns are formed on theboard portion and flexible flat cable portion, and the board portion isinserted in a synthetic resin casing in such a manner that the electricconductor patterns are exposed to the inner walls of the casing.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the structure of a molded resin casing of anelectronic part equipped with a flexible flat cable in accordance withthe present invention, in which FIG. 1(A) is a back view of the casing,FIG. 1(B) a side view of the casing and FIG. 1(C) a plan view of thecasing and FIG. 1(D) a plan view illustrating the structure of aterminal portion;

FIGS. 2 and 3 are views useful in describing a method of manufacturing aflexible board and a flat cable;

FIGS. 4(A), (B) and (C) are views useful in describing a method ofinserting the flexible board in the molded resin casing;

FIG. 5 is a sectional side view illustrating a rotary-type variableresistor fabricated using a molded resin casing of an electronic partwith a flexible flat cable;

FIG. 6 illustrates the structure of a molded resin casing of anelectronic part in which the casing has an internal flexible board inaccordance with another embodiment of the present invention, in whichFIG. 6(A) is a back view of the casing, FIG. 6(B) a side view of thecasing and FIG. 6(C) a plan view of the casing;

FIG. 7 is an exploded, perspective view illustrating a rotary-typevariable resistor using the molded resin casing shown in FIG. 6;

FIG. 8 is a sectional view showing the rotary-type variable resistor inthe assembled state;

FIG. 9 illustrates the structure of a molded resin casing of anelectronic part with a flexible flat cable in accordance with a thirdembodiment of the present invention, in which FIG. 9(A) is a plan viewof the casing, FIG. 9(B) a partial side section of the same and FIG.9(C) a back view;

FIGS. 10 and 11 are views useful in describing a method of manufacturinga flexible board and a flexible flat cable, respectively;

FIGS. 12(A) and (B) are views useful in describing a method of insertingthe flexible board in the molded resin casing;

FIG. 13 is a sectional side view illustrating the structure of asliding-type variable resistor fabricated using the molded resin casingof the electronic part with the flexible flat cable shown in FIG. 9;

FIGS. 14 and 15 are views illustrating the structure of a molded resincasing of an electronic part in which the casing has an internalflexible board with a flexible flat cable in accordance with a fourthembodiment of the present invention, in which FIG. 14 is a perspectiveview, FIG. 15(A) a plan view of the casing, FIG. 15(B) a partial sidesection thereof, FIG. 15(C) a back view thereof and FIG. 15(D) asectional view taken along line A--A of FIG. 15(A);

FIG. 16 is a view for describing a method of manufacturing the flexibleflat cable and the flexible board;

FIG. 17 illustrates the structure of a variable resistor using themolded resin casing with the flexible flat cable shown in FIG. 14, inwhich FIG. 17(A) is a partial side section [a sectional view taken alongline E-E of FIG. 17(B)] and FIG. 17(B) is a sectional view taken alongline F--F of FIG. 17(A);

FIGS. 18(A), (B) and (C) are views useful in describing a method ofinserting the flexible board in the molded resin casing;

FIG. 19 is a perspective view illustrating the structure of a moldedresin casing of an electronic part with a flexible flat cable inaccordance with a fifth embodiment of the present invention; and

FIG. 20 is a sectional view illustrating a rotary-type variable resistorusing the molded resin casing of FIG. 19.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the invention will now be described withreference to the drawings.

FIG. 1 illustrates the structure of a molded resin casing of anelectronic part equipped with a flexible flat cable in accordance withthe present invention, in which (A) is a back view of the casing, FIG. 1(B) is a side view of the casing, FIG. 1 (C) a plan view of the casingand FIG. 1 (D) a plan view showing the structure of a terminal in a casewhere the end of the flexible flat cable is provided with terminals. Inthis embodiment, the description will relate to a rotary-type variableresistor as an example of the electronic part.

As illustrated in the figures, a casing 1 of a rotary-type variableresistor has a flexible board 3 inserted therein, and a flexible flatcable 12 formed integrally with the flexible board 3 extends outwardlyfrom the side of the casing 1. The end of the flexible flat cable 12 isprovided, when required, with a terminal portion 2 having metallicterminal pieces 2-1 through 2-5.

The interior of the molded casing 1 is generally circular in shape andis provided with a side wall 1-2 along its periphery. The bottom of thecasing 1 is provided at its central portion with a support 1-1 on whicha rotary slider, described below, is supported for free rotation. Theback side of the molded casing 1 is formed to have protrusions 1-3, 1-4.

The flexible board 3 includes collector patterns 3-1, 3-2 and resistorpatterns 3-3, 3-4 formed on a resin film by printing. These collectorpatterns 3-1, 3-2 and resistor patterns 3-3, 3-4 on flexible board 3 areexposed at the bottom of the casing 1.

Wiring patterns 12-1 through 12-5 continuous with the end portions ofthe collector patterns 3-1, 3-2 and resistor patterns 3-3, 3-4 areformed on the flexible flat cable 12, and the wiring patterns areelectrically insulated by forming a resin coating layer on the flexibleflat cable 12 except at a portion thereof serving as a terminal portion12-6.

The structure, shape and method of manufacture of the components makingup the foregoing rotary-type variable resistor casing will now bedescribed.

FIG. 2 is a view useful in describing the structure and method ofmanufacturing the flexible board 3 formed integrally with the flexibleflat cable 12 and inserted in the molded resin casing of the rotary-typevariable resistor set forth above.

To manufacture the flexible board 3 formed integrally with the flexibleflat cable 12, first a strip of thermoplastic, heat-resistant syntheticresin film is prepared. The collector patterns 3-1, 3-2 and the resistorpatterns 3-3, 3-4 are formed on predetermined portions of the syntheticresin film by printing, thereby defining a portion corresponding to theflexible board 3, and the wiring patterns 12-1 through 12-5 continuouswith the collector patterns 3-1, 3-2 and resistor patterns 3-3, 3-4 areformed on the flexible flat cable 12. After these patterns are formed,the synthetic resin film is cut, leaving the portions corresponding tothe flexible flat cable 12 and the flexible board 3 and support strips10, 11 at the upper and lower ends. In this way a number of flexibleboards 3 integrated with the flexible flat cables 12 and connected bythe support strips 10, 11 can be made. In this case, it is obvious thatthe formation of the collector patterns 3-1, 3-2, resistor patterns 3-33-4 and wiring patterns 12-1 through 12-5 by printing can be carried outafter the synthetic resin film is cut leaving the portion correspondingto the flexible board 3 and support strips 10, 11. Examples of thesynthetic resin film are films made of polyparabanic acid, polyetherimide and polyethylene terephthalate.

In a case where the end portion of the flexible flat cable 12 isprovided with the terminal portion 2, as shown in Fig. (D) the metallicterminal pieces 2-1 through 2-5 formed integrally with a support strip20 are prepared, as shown in FIG. 3, an electrically conductive adhesivelayer is formed on the end portions of the wiring patterns 12-1 through12-5 on the flexible flat cable 12, and the tips of the metallicelectrode pieces 2-1 through 2-5 are placed on respective ones of theseend portions to be joined thereto by the adhesive.

Next, a reinforcing sheet 2-6 made of a synthetic resin film of asubstance the same as that of the flexible flat cable 12 is placed onthe metallic terminal pieces 2-1 through 2-5 that have been joined tothe wiring patterns 12-1 through 12-5, a horn (not shown) for emittingultrasonic waves is placed upon portions (indicated at 2-7 in FIG. 1) ofthe reinforcing sheet 2-6 at which the metallic terminal pieces 2-1through 2-5 are not present, and these portions are irradiated withultrasonic waves from the horn. As a result, the synthetic resin filmforming the reinforcing sheet 2-6 and the synthetic resin film formingthe flexible board 3 are fused locally by ultrasonic heating, so thatthe metallic terminal pieces 2-1 through 2-5 are rigidly secured ontothe respective wiring patterns 12-1 through 12-5 by the contractileforce of the synthetic resin films.

The metallic terminal pieces 2-1 through 2-5 are then heated by aheating iron from above the reinforcing sheet 2-6 or flexible board 3 tomelt the aforementioned electrically conductive adhesive layer, therebyreliably bonding the metallic terminal pieces 2-1 through 2-5 onto thewiring patterns 12-2 through 12-5.

It should be noted that since the synthetic resin films are stronglyfused together by the ultrasonic heating process, it may be permissiblein certain cases to omit the step in which the wiring patterns 12-1through 12-5 and the metallic terminal pieces 2-1 through 2-5 are bondedtogether by the electrically conductive adhesive. Next, by cutting alonglines A--A, B--B and C--C in FIG. 3(A), the flexible flat cable 12having the terminal portion 2 and the flexible board 3 are completed.

A method of inserting the flexible board 3 formed integrally with theflexible flat cable 12 having the foregoing construction into the resinmolded casing 1 will now be described.

As shown in FIG. 4(A), the flexible board 3 is clamped between a firstdie A and a second die B.

The first die A has a planar, flat surface A1 formed in its centralportion, an annular groove S2 formed about the periphery of the flatsurface A1, and a columnar hole A3 formed in the central portion of theflat surface A1. The flat surface A1 is closely contacted by thecollector patterns 3-1, 3-2 and resistor patterns 3-3, 3-4 of theflexible board 3, the annular groove A2 forms the side wall 1-2 of themolded casing 1, and the hole A3 forms the support 1-1 of the moldedcasing 1.

The second dies B is formed to have a recess B1 in a portion to whichthe flat surface A1 and annular groove A2 of the first die A correspond,a channel B2 of a prescribed width for prompting the inflow of moltenresin toward the terminal portion 2 of the flexible board 3, and afilling bore B3 formed substantially at the central portion of thechannel B1. The recess B1 is for forming the bottom portion of the resinmolding casing 1, and the channel B2 is for facilitating the inflow ofmolten resin along the back surface of the flexible board in thedirection of the flat cable 12, which is formed integral with theflexible flat board 3, when the molten resin is introduced underpressure from the filling bore B3.

As shown in FIG. 4B, a molten resin material (e.g., polyphenylenesulfide, polyethylene terephthalate or the like) is injected underpressure from the filling bore B3 of the second die B, as indicated bythe arrow D1. Owing to this injection of the molten resin, the moltenresin fills the recess B1 and channel B2 of the second die B as well asthe annular groove A2 of the first die A, and the synthetic resin filmforming the flexible board 3 is punctured by the synthetic resinmaterial, which therefore is allowed to fill the hole A3 that forms thesupport 1-1 of the molded casing 1, as indicated by arrow D2. Thus, thehole A3 which forms the support 1-1 is filled with the molten resinmaterial that burst through the flexible board 3, thereby bringing thesynthetic resin film into close contact with the inner surface of thehole A3 so that the film will not peel away from this inner surface.

If, instead of adopting the foregoing method, an inflow hole forallowing inflow of the molten resin material were to be providedbeforehand in a portion of the flexible board 3 corresponding to theposition of the hole A3, the molten resin material which has flowed intothe hole A3 through the inflow hole would impact against the innersurface of the hole A3 and reverse in direction. Consequently, thisportion of the synthetic resin material would makes its way between theflexible board 3 and the wall surface of the first die A, therebycausing the flexible board 3 to separate from the wall surface of thefirst die A so that the surfaces of the collector patterns 3-1, 3-2 andresistor patterns 3-3, 3-4 of the flexible board 3 would become coveredwith the resin material. The result would be a defective product.

However, in accordance with the present embodiment, this problem issolved by allowing the flexible board 3 to be punctured by the injectionof the molten resin material, as described above, instead of adoptingthe arrangement in which the flexible board 3 is provided with theinflow hole in advance.

If the second die B were not formed to have the channel B2, the moltenresin material at the time of filling operation would flow around thedie from the recess B1 through the surrounding annular groove A2 andwould first fill the die from the upper surfaces of the flexible board 3and flexible flat cable 12, which are situated below the annular grooveA2, as a result of which the terminal portion 2 of the flexible board 3would be urged downwardly toward the recess B1 of the second cavity B.In extreme cases, there is the danger that this might cause the flexibleboard 3 and flexible flat cable 12 to become exposed at the back surfaceof the casing.

In this embodiment, the foregoing problem is avoided by forming thechannel B2 in the second die B so that the flow of the molten resinmaterial from the central portion of the recess B1 to the flexible flatcable 12 will be fastest at the portion (the direction indicated byarrow D3) where it flows in through the channel B2. Therefore, theperiphery of the terminal portion 2 of the flexible board 3 is filledwith the molten resin material while the terminal portion 2 is urgedagainst the wall of the first die A. In other words, since a forceindicated by arrow D3 acts before a force produced by the inflow of themolten resin material in the direction of arrow S4 in Fig. 4(B), theterminal portion 2 will not be peeled off the first die A.

After the clearance between the first die A and the second die B is thusfilled with the molten resin material and the latter is allowed tosolidify, the first and second dies A, B are parted. The result is amolded resin casing of an electronic part equipped with a flexible flatcable in which the flexible board 3 of the kind shown in FIG. 1 isinserted in the molded resin casing 1.

It should be noted that the raised surface 1-5 on the back side of themolded casing 1 shown in (A) and (B) of FIG. 1 is formed by the channelB2 of second die B.

In the embodiment described above, the flexible board 3 is not formed tohave a molten resin inflow hole at the portion corresponding to theposition of the hole A in the first die A. However, if the flexibleboard 3 is formed beforehand to have a molten resin inflow hole 3a, asshown in (C) of FIG. 4, the molten resin material which has flowed intothe hole 3a can be prevented from seeping between the flexible board 3and the wall surface of the first die A if the diameter d₂ of the hole3a is made less than one-half the diameter d₁ of the hole A3 for formingthe support 1-1. It has been confirmed that the flexible board 3 willnot separate from the wall surface of the first die A is such anarrangement is adopted.

FIG. 5 is a sectional side view illustrating a rotary-type variableresistor in which use is made of the above-described molded resin casinghaving the flexible flat cable.

As shown in FIG. 5, a rotor 5 has a structure comprising a disk-shapedrotor main body 5-1 consisting of a synthetic resin, and a slider 5-2furnished on the bottom surface of the rotor main body 5-1. The support1-1 of the molded casing 1 is inserted into a hole formed in the centralportion of the rotor main body 5-1, and the rotor 5 is freely rotatablysupported within the molded casing 1 by thermally caulking the distalend of the support 1-1. Rotating the rotor 5 causes contacts on theslider 5-2 to slide on the collector patterns 3-1, 3-2 and resistorpatterns 3-3, 3-4 formed on the flexible board 3, thereby changing theresistance values between the wiring patterns 12-1 through 12-5 on theflexible flat cable 12.

If the rotary-type variable resistor having the above-describedconstruction is mounted on a printed circuit board 100, the variableresistor is positioned and attached using the protrusions 1-3, 1-4formed on the back surface of the molded casing 1 near the opposingedges thereof. At such time the flexible flat cable 12 is free to bendwith respect to the printed circuit board 100. As a result, the flexibleflat cable 12 can be freely arranged within and led out to the exteriorof an electronic apparatus with ease.

By thus integrally forming the flexible flat cable 12 and the flexibleboard 3 of a synthetic resin film and integrating the flexible board 3with the molded resin casing 1 in the form of an insert within thecasing, not only it is no longer necessary to assemble the molded casing1 and the flexible board 3, but it is also possible to achieve areduction in size and thickness and dispense with the need to connectwires to the terminals of the part.

Further, it has been described in the foregoing embodiment that thepatterns are formed on the flexible board 3 by the printing applicationof an electrically conductive paste. However, the invention is notlimited to this embodiment. By way of example, it is possible to formthe patterns by forming an electrically conductive foil such as ofaluminum or copper on the synthetic resin film by adhesion using anadhesive or by vacuum deposition, followed by forming the foil intopredetermined pattern shapes by an etching treatment.

FIG. 6 illustrates the structure of a molded resin casing of anelectronic part equipped with a flexible flat cable in accordance with asecond embodiment of the present invention, in which (A) is a back viewof the casing, (B) a side view of the casing and (C) a plan view of thecasing. The wiring patterns 12-1 through 12-5 continuous with the endportions of the collector patterns 3-1, 3-2 and resistor patterns 3-3,3-4 are formed on the flexible flat cable 12, and the wiring patternsare electrically insulated by forming a resin coating layer on theflexible cable 12 except at a portion thereof serving as the terminalportion 12-6. The flexible board 3 and a portion of the flexible flatcable 12 are inserted in the molded resin casing 1. The method ofmanufacturing this molded resin casing of an electronic part internallyaccommodating the above-described flexible board is the same as that forthe casing shown in FIG. 1 and need not be described again.

The end portion 12-6 of the flexible flat cable 12 may be provided withthe terminal portion 2 having the metallic terminal pieces 2-1 through2-5.

FIG. 7 is an exploded, perspective view illustrating a rotary-typevariable resistor using the molded resin casing shown in FIG. 6. Therotary-type variable resistor includes the molded resin casing 1, arotor 6, a cover plate 7 and a rotating knob 8.

The rotor 6 has the shape of a disk the central portion whereof isformed to have a columnar projection 6-4. The rotor 6 is also formed toinclude a pair of locking fingers 6-1, 6-2 on either side of theprojection 6-4 for the purpose of attaching the rotating knob 8, and aprojection 6-3 for limiting the rotation of the rotor 6 to apredetermined range. Though not shown, a slider 6-6 for coming intosliding contact with the collector patterns 3-1, 3-2 and resistorpatterns 3-3, 3-4 of the flexible board 3 is attached to the lowerportion of the rotor 6 (see FIG. 8).

The cover plate 7 comprises a metal plate having a central portionformed to include a through-hole 7-2 through which the locking fingers6-1, 6-2 of the rotor 6 are passed, and four corner portions each formedto included a hole 7-1 through which a corresponding one of theprojections 1-7 of molded casing 1 is passed. The central portion of thefront edge of the cover plate 7 is provided with a downwardly projectingleg 703.

The rotating knob 8 is a disk-shaped member the periphery of which isroughened. As will be described below, a projection 8-4 (see FIG. 8) thecentral portion whereof is formed to have a hole 8-3 (FIG. 8) into whichthe projection 6-4 of rotor 6 is inserted is provided on the lowercentral portion of the rotating knob 8, and holes 8-2, 8-2 into whichthe locking fingers 6-1, 6-2 of rotor 6 are inserted are formed in theknob 8 on either side of the projection 8-4. The holes 8-2, 8-2 eachhave a wall face provided with a step portion engaged by thecorresponding locking finger.

FIG. 8 is a sectional view showing the rotary-type variable resistorcomprising the foregoing components in the assembled state mounted onthe printed circuit board 100.

To assemble the rotary-type variable resistor, the rotor 6 is placed onthe molded resin casing 1 with the support 1-1 formed on the centralportion of the molded resin casing 1 being inserted into the hole 6-5formed in the lower central portion of the rotor 6. next, theprojections 1-7 at the four corners of the molded resin casing 1 areinserted into the holes 7-1 at the four corners of the cover plate 7 andthe tips of the projections 1-1 are thermally caulked, thereby attachingthe casing 1 to the cover plate 7. Thus, the projection 6-3 and the pairof locking fingers 6-1, 6-2 of the rotor 6 are passed through thethrough-hole 7-2 of the cover plate 7.

Next, the projection 6-4 of rotor 6 is inserted into the hole 8-3 formedin the projection 8-4 on the bottom of rotating knob 8, and the lockingfingers 6-1, 6-2 are inserted into the holes 8-2, 8-2 and made to engagethe step portions formed on the wall faces of the holes 8-2, 8-2,thereby attaching the rotating knob 8 to the rotor 6.

When the rotating knob 8 in the rotary-type variable resistor having theforegoing construction is turned, the rotor 6 rotates so that the slider6-6 attached to the lower portion thereof is brought into slidingcontact with the collector patterns 3-1, 3-2 and resistor patterns 3-3,3-4, on the flexible board 3. When the rotor 6 rotates a predeterminedamount, the projection 6-3 formed on the circumferential portion thereofabuts against a projection 1-8 formed on the inner peripheral surface ofthe casing side wall 1-2. As a result, the rotation of rotor 6 islimited to a predetermined range.

In the foregoing embodiment, an example has been described in which themolded casing is that of a rotary-type variable resistor. However, themolded casing can also be used as the molded casing of an internallyaccommodated flexible board of a rotary-type electronic part such as arotary-type code switch. In such case, most of the component parts ofthe above-described embodiment can be utilized, and only the shapes ofthe electric conductor patterns formed on the flexible board 3 need bechanged.

FIG. 9 illustrates the structure of a molded resin casing of anelectronic part equipped with a flexible flat cable in accordance with athird embodiment of the present invention, in which: (A) is a plan viewof the casing; (B) a partial side section of the same; (C) a back view;and (D) a sectional view taken along line A--A of FIG. 9(A).

In this embodiment, the casing is that of a slidingtype electronic partequipped with a flexible flat cable. As illustrated, the casing of thissliding-type electronic part includes a flexible board portion 53 and aflexible flat cable 62 integrally formed of a thermoplastic,heat-resistant film 51, with the flexible board portion 53 beinginserted into a molded resin casing 54.

Resistor patterns 53-1 and collector patterns 53-2 are formed on theflexible board portion 53 by printing, and electric conductor patterns62-1 continuous with the end portions of the collector patterns 53-2 andresistor patterns 53-1 are formed on the flexible flat cable 62 byprinting. In addition, the surface of the flexible cable portion 53 onwhich the resistor patterns 53-1 and the collector patterns 53-2 areformed is exposed at the bottom portion of the molded resin casing 54 inthe interior thereof.

The structure, shape and method of manufacture of the components makingup the foregoing sliding type variable resistor casing will now bedescribed.

FIG. 10 is useful in describing a process for manufacturing the flexibleboard portion 53 and the flexible flat cable 62. A heat-resistant film51 is connected to support strips 51-1, 51-1 at both ends. The tworesistor patterns 53-1, 53-1 and the two collector patterns 53-2, 53-2are formed by printing on the surface of the heat-resistant film 51 atpredetermined positions, and the conductor patterns 62-1 are printed onthe heat-resistant film so as to be continuous with both ends of theresistor patterns 53-1, 53-1. Conductor patterns 62-1, 62-1 are printedon one end of each of the collector patterns 53-2, 53-2.

The portions of the heat-resistant film 51 on which the resistorpatterns 53-1 and collector patterns 53-2 are formed by printing definethe flexible board portion 53 which serves as the board of thesliding-type resistor, and the portions of the heat-resistant film 51 onwhich the conductor patterns 62-1 are formed define the flexible flatcables 62. An insulative coating film is applied to the upper portion ofthe electric conductor patterns 62-1, 62-1 with the exception of the endportions 62-3.

If the end portion of each flexible flat cable 62 is provided a terminalportion, metallic terminal pieces 55 formed integral with a supportingstrip 58, as shown in Fig. 11, are placed on the end portions of theelectric conductors 62-1 of flexible flat cable 62. A hot-meltelectrically conductive adhesive layer is formed on the electricconductor patterns 62-1 of the flexible flat cables 62, the metallicelectrode pieces 55 are placed on respective ones securing film 57 of asubstance the same as that of the heat-resistant film 51 is placed onthe metallic terminal pieces 55 from above, and portions of the terminalsecuring film 57 at which the metallic terminal pieces 55 are notpresent are irradiated with ultrasonic waves from a horn (not shown)which emits ultrasonic waves. As a result, the terminal securing film 57and the heat-resistant film 51 of the flexible flat cable portions 62are locally fused by ultrasonic heating, so that the metallic terminalpieces 55 are rigidly bonded to the respective electric conductorpatterns 62-1.

The metallic terminal pieces 55 are then contacted and heated by aheating iron from above the terminal securing film 57 or theheat-resistant film 51 of the end portion 62-3 to melt theaforementioned electrically conductive adhesive layer, thereby reliablybonding the metallic terminal pieces 55 onto the electric conductorpatterns 62-1. As a result, terminals having an arrangementapproximately the same as in FIG. 1(D) are formed. After the flexibleboard 53 formed integral with the flexible flat cables 62 is inserted inthe molded resin casing 54 as mentioned above, the supporting strips51-1, 51-1 are cut away, thereby completing the molded casing 54 of thesliding-type variable resistor.

If the end portion of the flexible flat cable 62 is provided with aterminal portion having the metallic terminal pieces 55, the supportstrip 58 is cut away along the line D-D in FIG. 11.

The side portions of the casing 54 are formed so as to cover the outerperipheries of the flexible board portion 53 and the terminal portions52, as shown in FIG. 9, and four securing projections 54-2 for securinga cover plate, described below, and four guide projections 54-3 forguiding the cover plate are formed at both ends on one side portion54-1. The rear side of the casing is integrally formed to include twofixing projections 54-4, 54-4 for fixing the molded resin casing 54 to aprinted circuit board, described below.

Next, a method of inserting the flexible board portion 52 formedintegral with the flexible flat cables 62 into the molded resin casing54 will be described with reference to FIG. 12.

As shown in (A) of FIG. 12, the heat-resistant film 51 in which theflexible board portion 53 and the flexible flat cables 62 are integrallyformed is clamped between a first die A and a second die B.

The first die A is formed to have a flat surface A1 which is broughtinto close contact with the surface of the flexible board portion 53 ofthe heat-resistant film 51 having the resistor patterns 53-1 andcollector patterns 53-2 formed thereon, and a groove A2 for forming theside portions 54-1 of the molded casing 54. Though not shown, the bottomportion of the groove A2 is formed to have recesses for forming thesecuring projections 54-2 and the guide projections 54-3 of the moldedresin casing 54.

The second die B has a recess B1 for forming the bottom portion of themolded casing 54 formed at a portion thereof which corresponds to theflat portion A1 and groove A2 of the first die A, and a channel B2 of apredetermined width for promoting the inflow of a molten resin materialtoward the portions of the molded resin casing 54 penetrated by theflexible flat cables 62 of heat-resistant film 51. The channel B2 isformed longitudinally of the recess B1 at the approximate centerthereof. (An elongated projection on the rear side of the molding casing54 is formed by this channel B2.) The second die B also has columnarrecesses B3 formed at the center of the recess B1 at predeterminedpositions longitudinally thereof for forming the fixing projections54-4, 54-4 on the rear side of the molded casing 54. Though not shown,the peripheral portion of the bottom of recess B1 is formed to haverecesses for forming projections 54-6 on the molded casing 54.

Next, as shown in (B) of FIG. 12, a molten resin material (e.g.,polyphenylene sulfide, polyethylene terephthalate or the like) isinjected under pressure in the direction of the arrows D1 from fillingbores B4 formed at the base ends of the recesses B3 of the second die B.Owing to this injection of the molten resin, the heat-resistant film 51of the flexible board portion 53 is urged against the flat surface A1 ofthe first die A.

If the elongated channel B2 extending longitudinally along the center ofthe recess B1 of the second die B were not provided, the molten resinmaterial at the time of the charging operation would flow around the diefrom the recess B1 through the surrounding groove A2 and would fill thedie from the upper surface side of the flexible board portion 53 andflexible flat cables 62 at the grooves A2, as indicated by arrow D2. Asa result, the peripheral portions of the flexible board portion 53 andflexible flat cables 62 would be urged downwardly toward the recess B1of the second cavity B. In extreme cases, there is the danger that thismight cause the peripheral portions to become exposed at the backsurface of the molded casing 54.

In this embodiment, however, the foregoing problem is avoided by formingthe channel B2 longitudinally of the recess B1 along the center thereofin the second die B so that the flow of the molten resin material ispromoted by the channel B2. Accordingly, the injection of the moltenresin material is such that first the recess B1 is filled from thelongitudinal direction thereof along its center (the direction indicatedby arrow D3), then the periphery of the cavity and finally the grooveA2. During this filling process, therefore, the flexible board portion53 and the flexible flat cables 62 are urged against the side of thefirst die A, so that they will not separate from the flat surface A1 ofthe first die A. In other words, the molten resin material will not flowinto the area between the flat surface A1 of the first die A and theflexible board portion 53. Consequently, when the first and second diesA, B are parted after the molten resin material solidifies, as will bedescribed below, the surface of the flexible board portion 53 will becompletely exposed at the bottom of the molded resin casing 54.

After the molten resin material thus charged into the area between thefirst and second dies A, B has solidified, the first and second dies A,B are parted. As a result, a casing of a sliding-type variable resistorsuch as that shown in FIG. 9 is completed.

FIG. 13 is a sectional side view illustrating the structure of asliding-type variable resistor in which use is made of theabove-described sliding-type variable resistor casing equipped with theflexible flat cables.

As illustrated, a sliding body 59 is placed upon the flexible boardportion 53 inserted into the molded resin casing 54. Provided on thebottom portion of the sliding body 59 is a slider 60 brought intosliding contact with the resistor patterns 53-1 and collector patterns53-2 formed on the flexible board 53. The upper portion of the slidingbody 59 is formed integral with an operating lever 59a. A cover plate 61is placed upon the upper part of the side portions 54-1 of molded casing54 and the distal ends of the securing projections 54-2 are thermallycaulked, whereby the sliding body 59 is retained between cover plate 61and the flexible board portion 53. This completes the sliding-typevariable resistor.

When the operating lever 59a in the sliding-type variable resistorhaving the above-described structure is operated to move the slidingbody 59, the slider 60 slides on the resistor patterns 53-1 andcollector patterns 53-2 to change the positions at which the contacts ofthe slider 60 contact the resistor patterns 53-1, thereby changing theresistance between the electric conductor patterns 62-1 to the flexibleflat cables 62 connected to respective ones of the collector patterns53-2 and resistor patterns 53-1.

As described hereinabove, the flexible board portion 53 on which theresistor patterns 53-1 and collector patterns 53-2 are formed and theflexible flat cables 62 on which the electric conductor patterns 52-1are formed are made of the thermoplastic, heat-resistant film 51consisting of synthetic resin, and the heat-resistant film 51 isinsertion-molded in the molded casing 54 consisting of synthetic resin.As a result, not only is it no longer necessary to assemble the moldedcasing 54 and the flexible board portion 53, but it is also possible toreduce the size and thickness of the sliding-type variable resistor anddispense with the need to connect wires to the terminals of theelectronic part.

In the foregoing embodiment, the invention is described in connectionwith a sliding-type variable resistor. However, the invention can beapplied to a sliding-type code switch by changing the patterns formed onthe flexible board portion 53.

Further, it has been described in the foregoing embodiment that thepatterns are formed on the flexible board 53 by the printing applicationof an electrically conductive paste. However, the invention is notlimited to this embodiment. By way of example, it is possible to formthe patterns by forming an electrically conductive foil such as ofaluminum or copper on the synthetic resin film by adhesion using anadhesive or by vacuum deposition, followed by forming the foil intopredetermined pattern shapes by an etching treatment.

FIGS. 14 and 15 are views illustrating the structure of a molded resincasing of an electronic part in which the casing has a flexible flatcable in accordance with a fourth embodiment of the present invention,in which FIG. 14 is a perspective view, FIG. 15(A) a plan view of thecasing, (B) a partial side section thereon, (C) a back view thereof, and(D) a sectional view taken along line A--A of FIG. 15(A). In thisembodiment, a variable resistor will be described as the electronicpart.

As illustrated, a flexible flat board 73 inserted in a molded resincasing and flat cables 75 are integrally formed of a heat-resistant film71. Resistor patterns 73-1, 73-1 and collector patterns 73-2, 73-2 areprinted on the flexible board 73, and electric conductor patterns 75-1,75-1 continuous with end portions of the resistor patterns 73-1, 73-1are printed on the flexible flat cable 75. An insulating film is formedby application of a resin material to the upper surface of each flexibleflat cable 75 with the exception of the end portion thereof. Theresistor patterns 73-1, 73-1 on the flexible board 73 are exposed at thebottom surface of the casing, and the collector patterns 73-2, 73-2 areexposed at the two opposing inner side wall surfaces of the casing.

The arrangement and method of manufacture of the components making upthe foregoing electronic part casing will now be described.

FIG. 16 is a view useful in describing a process for manufacturing theflexible board 73 and the flexible flat cables 75. The flexible flatboard 73 and flat cables 75 are connected to support strips 71-1, 71-1integrally formed of heatresistant film. Examples of the material usableto form the heat-resistant film 71 are polyparabanic acid, polyetherimide and polyethylene. Two resistor patterns 73-1, 73-1 and twocollector patterns 73-2, 73-2 are printed on the surface of theheat-resistant film 71 at predetermined positions to define a flexibleboard 73, and electric conductor patterns 75-1, 75-1 are printed on theflexible flat cables 75 that are continuous with the flexible board 73.The resistor patterns 73-1, collector patterns 73-2 and electricconductor patterns 75-1, 75-1 are connected in such a manner that oneend of each resistor pattern 73-1 is connected to one end of thecorresponding collector pattern 73-2 and one end of an electricconductor pattern 52-1 is connected to the junction of the resistor andcollector patterns 73-1, 73-2. The width of the flexible board 73 of theheat-resistant film 71 is a predetermined dimension larger than thewidth of the flexible flat cable 75.

As set forth above, the flexible board portion 73 is inserted into themolded synthetic resin casing 74 in such a manner that the flexible flatcables 75 project to the outside. Thereafter, the support strips 71-1,71-1 are removed thereby completing the molded casing of the electronicpart having a flexible flat cable.

The side portions 74-1 of the molded resin casing 74 are formed so as tocover the outer peripheries of the flexible board portion 73 and theterminal portions 72, and projections 74-3 serving as stoppers areformed at both ends on one side of the casing 74. In addition, slopingsurfaces 74-2 which slope inwardly of the casing 74 are formed atpredetermined positions on the tops of the side portions 74-1.

Next, a method of inserting the flexible board 73 formed integral withthe flexible flat cables 75 into the molded resin casing 74 will bedescribed with reference to FIG. 18.

First, as shown in FIG. 18(A), the flexible board 73 and the flexibleflat cables 75, 75 integrally formed of the heat-resistant film areclamped between a first die A and second die B.

The first die A is formed to have a flat surface A1 which is broughtinto close contact with the surface of the flexible board 73 of theheat-resistant film 71 having the resistor patterns 73-1, 73-1 formedthereon, and a groove A2 provided around the flat surface A1 for formingthe side portions 74-1 of the molded casing 74.

The second die B has a recess B1 for forming the bottom portion of themolded casing 74 formed at a portion thereof which corresponds to theflat surface A1 and groove A2 of the first die A. In addition,projections B2, B2 are provided in the recess B1 at a predeterminedspacing for the purpose of impeding the flow of a molten resin materialin the longitudinal direction of the heat-resistant film 71 andpromoting the flow of the molten resin material in the lateral directionof the film 71. Further, a filling bore B3 for charging a molten resinmaterial is formed in the center of the recess B1.

A molten resin, such as polyphenylene sulfide, polyethyleneterephthalate or the like, is introduced from the filling bore B3 underpressure as indicated by the arrow D1. Owing to the injection of themolten resin, the resin material flows into the recess B1 of the seconddie B. The flow of the resin material in the lateral direction (at rightangles to the plane of the drawing) of the heat-resistant film 71 ispromoted by the projections B2 formed in the recess B1, as shown in (C)of FIG. 18. As a result, the flexible board 73 of the heat-resistantfilm 71 is urged by the molten resin material and bent along one sidesurface of the groove A2, as shown in (B) of FIG. 18, so that thecollector patterns 73-2 are brought into close contact with the sidesurface.

If the recess B1 of the second die B were not provided with theprojection B2, the molten resin would flow radially from the fillingbore B3 when introduced from the bore. In such case, the molten resinmaterial which flows longitudinally of the recess B1 would flow into thegroove A2 from the side portions of the flexible flat cables 75 and partof this resin would enter the area between the side surface of thegroove A2 and the parts of the flexible board 73 on which the collectorpatterns 73-2 are formed, resulting in the surfaces of the collectorpatterns 73-2 being covered with the resin material. However, since inthis embodiment the projections B2 are formed on the bottom of therecess B1, the flow of the molten resin material in the longitudinaldirection of the recess B1 is impeded, while the flow of the moltenresin in the lateral direction of the heat-resistant film 71 ispromoted, Accordingly, the molten resin material which thus flows intothe groove A2 causes the surface of the flexible board 73 to be bentalong the slide surface of the groove A2, thus bringing the surface ofthe flexible board into close contact with the side surface of thegroove. Thus, the front surfaces of the collector patterns 73-2 offlexible board 73 will not be covered with the resin material.

More specifically, since the molten resin material will not flow intothe area between the side surfaces of the flat surface A1 of the firstdie A and the flexible board 73, when the first die A and second die Bare parted after the resin material has solidified, as described below,the resistor patterns 73-1, 73-1 on the flexible board 73 are exposed atthe bottom of the molded casing 74, and the collector patterns 73-2,73-2 are exposed at the two opposing inner side walls.

After the molten resin material thus charged in the cavity between thefirst and second dies A, B has solidified, the first and second dies areparted. As a result, a variable resistor casing such as that shown inFIG. 14 is completed.

FIG. 17 shows the structure of a variable resistor fabricated using theabove-described molded resin casing 74, in which (A) is a partial sidesection [ a sectional view taken along line E--E of FIG. 17(B)] and (B)is a transverse sectional view [ a sectional view taken along line F--Fof FIG. 17(A)]. As illustrated, a slider 80 is provided on the outerperiphery of the variable resistor casing having the above-describedstructure. The slider 80 is molded of a resin material and has anoperating knob 81 integral with one side portion thereof. Numeral 83denotes contacts in sliding contact with the resistor patterns 73-1,73-1 on the flexible board 73. Numeral 84 denotes contacts in slidingcontact with the collector patterns 73-2. The contact 83 and 84 areformed integral with each other in the form of a contact member 85,which is inserted in the body of the slider 85. Further, a pair ofengagement members 82, 82 that are engaged with two edge portions of theouter surface of the bottom of molded casing 74 are formed on both sidesof the slider 80.

With the upper part of the molded casing 74 abutting against theengagement members 82, 82 of the slider 80 having the above-describedstructure, the slider 80 is pressed. As a result, the engagement members82 are spread apart, in which state they descend along the outer sidesurfaces of the slider 80 and, eventually, the respective projections ofthe engagement members 82, 82 engage with the outer peripheral bottomsurface of the casing 74. Thus, a variable resistor prepared using themolded resin casing 74 is completed.

When the operating knob 81 of the variable resistor having theabove-described construction is operated to move the slider 80longitudinally of the molded resin casing 74, the contacts 83, 84 arecaused to slide on the respective upper surfaces of the resistorpatterns 73-1 and collector patterns 73-2, thus causing a change in theresistance between the electric conductor patterns 75-1, 75-1 of theflexible flat cables 75.

In the foregoing embodiment, an arrangement has been described in whichthe collector patterns 73-2 on the flexible board 73 are exposed at thetwo opposing inner side wall surfaces of the molded casing 74. However,the collector patterns 73-2 may be exposed at one inner side surface ofthe casing 74. Further, it is of course possible to vary the number ofresistor patterns 73-1 and collector patterns 73-2 according to need. Inaddition, it is obvious that an arrangement can be adopted in which theresistor patterns 73-1, 73-1 are exposed at the inner side wall surfacesand the collector patterns 73-2, 73-2 are exposed at the bottom surface.

As has been described above, the flexible board 73 formed with theresistor patterns 73-1, 73-1 and collector patterns 73-2, 73-2 and theflexible flat cables 75 formed with the electric conductor patterns75-1, 75-1 are integrally formed using a heat-resistant film 71 of athermoplastic resin, and the flexible board 73 is arranged in such amanner that the resistor patterns 73-1, 73-1 are exposed at the bottomsurface of the casing 74, while the collector patterns 73-2, 73-2 areexposed at the two opposing inner side wall surfaces. Therefore, it isimpossible to effectively utilize the inner surfaces of the moldedcasing 74 and, hence, reduce the size and thickness of the variableresistor, and it is no longer necessary to assemble the flexible board73 and the molded casing 74 together. In addition, since the casing isequipped with the flexible flat cables, it is no longer necessary toconnect wiring to the terminal portions if the molded casing is used.

Although in the above-described embodiments the present invention hasbeen described by way of example in which the invention is applied to asliding-type variable resistor, it should be noted that the moldedcasing of the invention is not limited thereto but can be utilized asthe molded casing of a sliding-type switch as well. For example, it ispossible to fabricate a miniature multiple-bit code switch by formingfixed contact patterns of a code switch on the inner bottom surface andboth inner side surfaces of the above-described molded resin casing 74.

Further, it has been described in the foregoing embodiment that thepatterns are formed on the flexible board 73 by the printing applicationof an electrically conductive paste. However, the invention is notlimited to this embodiment. By way of example, it is possible to formthe patterns by forming an electrically conductive foil such as ofaluminum or copper on the synthetic resin film by adhesion using anadhesive or by vacuum deposition, followed by forming the foil intopredetermined pattern shapes by an etching treatment.

FIG. 19 is a perspective view illustrating the structure of a moldedresin casing of an electronic part equipped with a flexible flat cablein accordance with a fifth embodiment of the present invention. In thisembodiment, the flexible board 93 is inserted into a molded resin casing91 so as to be exposed at the inner surface of a side wall 91-2 and theouter peripheral surface of a support 91-1 of the casing 91. Here aflexible flat cable 92 formed integral with the flexible flat cable 93extends outwardly from the side portion of the molded resin casing 91.The method of inserting the flexible board 93 into the molded casing 91is substantially the same as the method indicated in FIG. 4 and need notbe described again.

By adopting this arrangement, a resistor pattern 93-4 is exposed at theinner surface of the side wall 91-2 of the molded resin casing 91, aresistor pattern 93-3 and a collector pattern 93-2 are exposed at theinner bottom surface, and a collector pattern 93-1 is exposed at theouter peripheral surface of the support 91-1. Further, the flexible flatcable 92 extends from the side portion of the molded resin casing 91.With the exception of a terminal portion 92-2, the flexible flat cable92 has its upper surface coated with a resin material that forms aninsulative film.

FIG. 20 is a sectional view showing the rotary-type variable resistor,which is fabricated using the molded resin casing 91 having theabove-described construction, mounted on the printed circuit board 100.The structure of this arrangement is substantially the same as that ofthe rotary-type variable resistor of FIGS. 7 and 8.

To assemble this rotary-type variable resistor, a rotor 96 is placed onthe molded resin casing 91 with the support 91-1 formed on the centralportion of the molded resin casing 91 being inserted into a hole 96-5formed in the lower central portion of the rotor 96. Locking fingers96-1, 96-2 are inserted into holes 98-2, 98-2 and made to engage stepportions formed on the wall surfaces of the holes 98-2, 98-2, therebyattaching the rotating knob 98 to the rotor 96.

When the rotating knob 98 in the rotary-type variable resistor havingthe foregoing construction is turned, the rotor 96 rotates so that aslider 96-6 attached to the lower surface thereof is brought intosliding contact with the resistor pattern 93-2 and collector pattern93-2 exposed at the inner bottom surface of the casing 91, a slider 96-7attached to the inner peripheral surface of the rotor 96 is brought intosliding contact with the collector pattern 93-1 exposed at the outerperipheral surface of the support 91-1, and a slider 96-8 attached tothe outer peripheral surface of the rotor 96 is brought into slidingcontact with the resistor pattern 93-3 exposed at the inner surface ofthe side wall 91-2. This causes the resistance between the electricconductor patterns 92-1, 92-1 of flat cable 92 to change.

By constructing the molded resin casing in the manner described above,the inner surface of the molding casing 91 can be utilized effectivelyto make it possible to greatly reduce the size of the rotary-typevariable resistor.

Although in the above-described embodiments the present invention hasbeen described by way of example in which the invention is applied to avariable resistor, it should be noted that the molded casing of theinvention can be utilized as the molded casing of a rotary-type codeswitch or the like by changing the various patterns formed on theflexible board.

Further, in the foregoing embodiment, the patterns can be formed on theflexible board 93 by the printing application of an electricallyconductive paste, and it is possible to form the patterns by forming anelectrically conductive foil such as of aluminum or copper on thesynthetic resin film by adhesion using an adhesive or by vacuumdeposition, followed by forming the foil into predetermined patternshapes by an etching treatment.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope itself, it is tobe understood that the invention is not limited to the specificembodiments thereof except as defined in the appended claims.

We claim:
 1. A device comprising:a molded resin casing, and said resincasing having means for receiving a flexible board therein; a flexibleboard integrally attached to and received in said receiving means ofsaid molded resin casing, said flexible board including a syntheticresin film having a first plurality of electrical conductor patternsdefined thereon, and means on said flexible board for slidably receivingan electronic part for electrically contacting an electronic part withsaid first plurality of electrical conductor patterns, said flexibleboard being integrally attached to said molded resin casing when saidresin casing is molded by injecting a molten synthetic resin, and saidflexible board being oriented during the molding of said resin casingfor causing said first plurality of electrical conductor patterns to beexposed within said synthetic resin for contacting an electronic partreceived therein; and a flexible flat cable integrally attached to saidflexible board, said flexible flat cable including a synthetic resinfilm having a second plurality of electrical conductor patterns definedthereon, said second plurality of electrical conductor patterns beingdirectly electrically connected with said first plurality of electricalconductor patterns, and said flexible flat cable extending outwardlyaway from said synthetic resin casing.
 2. A device as in claim 1,wherein said flexible board is a predetermined amount larger than aninner bottom surface of said receiving means of said synthetic resincasing, and said first plurality of electrical conductor patterns isexposed to said inner bottom surface and an inner surface of a side wallof said receiving means of said synthetic resin casing.
 3. A device asin claim 1 or 2, wherein the interior of said receiving means of saidsynthetic resin casing is substantially circular in shape, a support forfreely rotatably supporting a rotor is integrally attached to saidsynthetic resin casing at a central portion thereof, and said firstplurality of electrical conductor patterns of said flexible board aredefined in substantially concentric circles and exposed to an innerbottom portion of said receiving means of said casing with said supportat the center thereof.
 4. A device as in claim 3, wherein said flexibleboard is a predetermined amount larger than an inner bottom surface ofsaid receiving means of said synthetic resin casing, and said firstplurality of electrical conductor patterns is exposed to said innerbottom surface of said casing and an outer peripheral surface of thesupport or an inner surface of a side wall of said receiving means ofsaid casing.
 5. A device as in claim 1 or 2, wherein the interior ofsaid receiving means of said synthetic resin casing is substantiallyrectangular in shape for slidably receiving a slider of a sliding-typeelectronic component, and said first plurality of electrical conductorpatterns of said flexible board are defined substantially in parallelwith long sides of the substantially rectangular shape of said receivingmeans.
 6. A device as in claim 1, wherein a plurality of metallicterminal pieces is connected to an end portion of each of said secondplurality of electrical conductor patterns on an end portion of saidflexible flat cable, a securing resin film is disposed on said pluralityof metallic terminal pieces, and said securing resin film and saidsynthetic resin film of said flexible board are locally fused forproviding a terminal portion.